The present disclosure relates to an optical element, an optical system, an imaging apparatus, an optical instrument, and a stamper. Specifically, the present disclosure relates to an optical system including an optical element provided with a sub-wavelength structure body on a surface thereof.
In the related art, various techniques for suppressing surface reflection of light have been used in the technical field of the optical element. As one of the techniques, there is a technique where a sub-wavelength structure body is formed on an optical element surface (for example, refer to OPTICAL AND ELECTRO-OPTICAL ENGINEERING CONTACT, Vol. 43, No. 11 (2005), 630-637).
Generally, in a case where cyclic concave and convex shapes are provided on the optical element surface, diffraction occurs when light is transmitted therethrough, and the straightforward component of the transmitted light is considerably reduced. However, if the pitch of the concave and convex shapes is shorter than the wavelength of the transmitted light, the diffraction does not occur, and thus it is possible to achieve a good antireflection effect.
The above-described antireflection technique has an excellent antireflection characteristic, and thus an application thereof to various optical element surfaces has been reviewed. For example, there has been proposed a technique where a sub-wavelength structure body is formed on a lens surface (for example, refer to Japanese Unexamined Patent Application Publication No. 2011-002853).